The mayor repeats the same mistake in his 2017 plan and reduces shelter budgets when he should be increasing them, the IBO argued in a report released Monday.

The IBO projects the city’s shelters will come up $130 million short in 2017, in part because the permanent subsidy and supportive housing programs that the de Blasio administration expects to lower the shelter census need more time to bring down the population. The City Council might insist that the allocation be increased in the final budget, which is due by July 1 and requires council approval.

City Councilman Brad Lander, D-Brooklyn, told city budget director Dean Fuleihan at a hearing this month that the city had “perpetually underbudgeted” for homelessness for years.

“In the Bloomberg administration, it was my sense that we under-budgeted $50 million to $100 million every year on a sort of, fingers-crossed, 'maybe homelessness will go down this coming year,' without any real reason to believe it was going to,” Lander said.

“We are making historic investments in reducing homelessness and I praise the administration for taking them," he said at the hearing, "but I don’t think there’s reason to expect that next year’s shelter census is going to be 15% lower than this year’s.”

The family shelter population has recently stabilized—no small feat considering the ongoing waves of new shelter entrants. And the adult shelter population has increased by 11%, in part because Mayor Bill de Blasio has pushed his agencies to persuade single adults to move off the street and into shelters.

Meanwhile, permanent subsidy programs have been slower to take off than once expected. The administration is not on target to meet its goal of 8,322 households moved out of shelters into permanent housing by June, IBO found.

But the mayor's proposed family shelter budget for fiscal 2017 is $553 million, $72 million less than planned spending for fiscal 2016, which ends June 30. The proposed adult shelter budget is $325 million, a $120 million drop from this year.

At the March 1 budget hearing, Fuleihan said he hoped additional state funding would supplement the city’s shelter budget and boost the numbers of those exiting shelters.

Also, an overhaul at the Department of Homeless Services could bring about a change in the allocation, according to a mayoral spokeswoman. “ A comprehensive 90-day review is underway, and that assessment will directly inform future years’ spending,” she said.

City Hall defended its approach to the widely-dubbed “homelessness crisis.”

“The de Blasio administration is immediately and aggressively tackling this issue with the most comprehensive effort in the country to prevent homelessness and move people out of shelter and into permanent homes,” she said in a statement. “The homelessness crisis was created by years of disinvestment; it takes sustained resources and smart management to address it, and that’s exactly what this administration is doing."

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